The disclosure relates generally to reducing interference(s) in a wireless distribution system (WDS), such as a distributed antenna system (DAS) and, more particularly, to activating interference signal rejection filter path based on detection of an interference signal in the WDS.
Wireless customers are increasingly demanding digital data services, such as streaming video signals. At the same time, some wireless customers use their wireless communications devices in areas that are poorly serviced by conventional cellular networks, such as inside certain buildings or areas where there is little cellular coverage. One response to the intersection of these two concerns has been the use of distributed antenna systems (DASs). DASs include remote units configured to receive and transmit communications signals to client devices within the antenna range of the remote units. DASs can be particularly useful when deployed inside buildings or other indoor environments where the wireless communications devices may not otherwise be able to effectively receive radio frequency (RF) signals from a source.
In this regard, FIG. 1 illustrates distribution of communications services to remote coverage areas 100(1)-100(N) of a WDS provided in the form of a DAS 102, wherein ‘N’ is the number of remote coverage areas. These communications services can include cellular services (e.g., long-term evolution (LTE)), local area wireless services, such as RF identification (RFID) tracking, Bluetooth, and wireless local area network (e.g., Wi-Fi), and global positioning system (GPS) signal-based wireless solutions for location-based services, and combinations thereof, as examples. The remote coverage areas 100(1)-100(N) may be remotely located. In this regard, the remote coverage areas 100(1)-100(N) are created by and centered on remote units 104(1)-104(N) connected to a head-end equipment (HEE) 106 (e.g., a head-end controller, a head-end unit, or a central unit). The HEE 106 may be communicatively coupled to a signal source 108, for example, a base transceiver station (BTS) or a baseband unit (BBU). In this regard, the HEE 106 receives downlink communications signals 110D from the signal source 108 to be distributed to the remote units 104(1)-104(N). The remote units 104(1)-104(N) are configured to receive the downlink communications signals 110D from the HEE 106 over a communications medium 112 to be distributed to the respective remote coverage areas 100(1)-100(N) of the remote units 104(1)-104(N). In a non-limiting example, the communications medium 112 may be a wired communications medium, a wireless communications medium, or an optical fiber-based communications medium. Each of the remote units 104(1)-104(N) may include an RF transmitter/receiver (not shown) and a respective antenna 114(1)-114(N) operably connected to the RF transmitter/receiver to wirelessly distribute the communications services to client devices 116 within the respective remote coverage areas 100(1)-100(N). The remote units 104(1)-104(N) are also configured to receive uplink communications signals 110U from the client devices 116 in the respective remote coverage areas 100(1)-100(N) to be distributed to the signal source 108. The size of each of the remote coverage areas 100(1)-100(N) is determined by the amount of RF power transmitted by the respective remote units 104(1)-104(N), receiver sensitivity, antenna gain, and RF environment, as well as by RF transmitter/receiver sensitivity of the client devices 116. The client devices 116 usually have a fixed maximum RF receiver sensitivity, so that the above-mentioned properties of the remote units 104(1)-104(N) mainly determine the size of the respective remote coverage areas 100(1)-100(N). With reference to FIG. 1, the remote units 104(1)-104(N) may be configured to provide both the cellular services and the local area network services in adjacent RF spectrums. In this regard, FIG. 2 is a schematic diagram of an exemplary RF spectrum map 200 that includes RF bands for providing cellular and local area network services in the WDS 102 of FIG. 1. With reference to FIG. 2, the local area network services (e.g., Bluetooth and Wi-Fi) may be provided over a two point four gigahertz (2.4 GHz) industrial, scientific, and medical (ISM) band 202. As such, the Wi-Fi services are configured to operate between 2401 MHz and 2495 MHz of the ISM band 202. In a non-limiting example, the Wi-Fi spectrum includes fourteen (14) Wi-Fi channels (Ch1-Ch14). Among the 14 Wi-Fi channels, Ch1 lies between 2401 MHz and 2423 MHz, and Ch14 lies between 2473 MHz and 2495 MHz. The 2.4 GHz ISM band 202 may also be configured to support the Bluetooth services based on seventy nine (79) channels ranging 2402 MHz to 2480 MHz of the ISM band 202.
With continuing reference to FIG. 2, the LTE services, when configured according to a time-division duplex (TDD) mode, may be provided in a first LTE TDD band 204 and/or a second LTE TDD band 206. The first LTE TDD band 204, which is commonly referred to as LTE band forty (40), has a lower boundary 208 located at two thousand three hundred megahertz (2300 MHz) and an upper boundary 210 located at 2400 MHz. The second LTE TDD band 206, which is commonly referred to as LTE band forty one (41), has a lower boundary 212 located at two thousand four hundred ninety six megahertz (2496 MHz) and an upper boundary 214 located at two thousand six hundred ninety megahertz (2690 MHz).
As illustrated in FIG. 2, the upper boundary 210 of the LTE band 40 (2400 MHz) is merely separated from the Wi-Fi Ch1 (2401 MHz) by one (1) megahertz (1 MHz). Likewise, the lower boundary 212 of the LTE band 41 (2496 MHz) is merely separated from the Wi-Fi Ch14 (2495 MHz) by 1 MHz. As such, when the remote units 104(1)-104(N) of FIG. 1 are configured to concurrently provide LTE services in LTE band 41 and Wi-Fi services in the Wi-Fi Ch14 for example, RF interferences may occur between the LTE services and the Wi-Fi services due to insufficient spectrum separation between the LTE band 41 and the Wi-Fi Ch14. In this regard, it may be desired to provide additional spectrum protection in the remote units 104(1)-104(N) to optimize RF performance of the WDS 102.
No admission is made that any reference cited herein constitutes prior art. Applicant expressly reserves the right to challenge the accuracy and pertinency of any cited documents.